Error referencing an inner class View in layout/main.xml

Question

Grrr...

I create a subclass of view as an inner class in my Activity. Before I simply linked to this view from my activity with:

setContentView(new CustomView(this));

without problems.

Now, however, my view is getting more complex so I am making it part of a FrameLayout so that I can make this the base view and add a Spinner widget on top of it. The problem is, when I do this I get an error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.grafightscratch.ochemmer/com.grafightscratch.ochemmer.MoleculeTablet}: android.view.InflateException: Binary XML file line #4: Error inflating class com.grafightscratch.ochemmer.MoleculeTablet.MoleculeTabletView
...
Caused by: android.view.InflateException: Binary XML file line #4: Error inflating class com.grafightscratch.ochemmer.MoleculeTablet.MoleculeTabletView
...
Caused by: java.lang.ClassNotFoundException: com.grafightscratch.ochemmer.MoleculeTablet.MoleculeTabletView in loader dalvik.system.PathClassLoader@43b74a28

So- this view worked before when I linked to it directly, but when I tried to add it in the main.xml file as part of a framelayout I got the above error. I also tried putting into a layout with only it being displayed via:

<com.grafightscratch.ochemmer.MoleculeTablet.MoleculeTabletView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/molecule_tablet_view"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>

Nothing works. I keep getting the InflateException/ClassNotFoundException errors. It complains about "line #3" in the binary XML file, and if it is talking about main.xml that is the package declaration which I have triple checked.

EDIT I tried making this view a separate class (ie- not an inner class) and it works. After some searching around I found some posts saying that the xml tag should look like this:

<com.grafightscratch.ochemmer.MoleculeTablet$MoleculeTabletView ...>

Ie, a dollar sign should be used to separate the innerclass from the main class. However, Eclipse barfs on this, calls it an error, and refuses to let me build or deploy with that character there. So now the question becomes: how does one reference a View that is an inner class?

Answer 1

You need to specify the fully qualified name of your view class in the XML for inflation to work and View Class to be found by the Runtime System.
Since you have declared your View as inner class of your activity the fully qualified name would be: <your_package_name>.OuterClassName.InnerClassName

Are you sure com.grafightscratch.ochemmer.CustomView is the fully qualified name of your class?

EDIT: Thanks for reminding me of this. When the views are declared as nested classes there is a slight aberration, see Use Custom component of this document.

Answer 2

For inner classes the syntax becomes:

<view class="com.grafightscratch.ochemmer.MoleculeTablet$MoleculeTabletView" />

The reason is that $ is an illegal character in XML tags.

Answer 3

I'm using the correct syntax on my XML and still im getting the inflate error